1. Field of the Invention
The present invention relates generally to the control of downhole tools, and more particularly to single control line actuation of downhole tools.
2. Description of the Related Art
The following descriptions and examples are not admitted to be prior art by virtue of their inclusion in this section.
Many hydraulically actuated downhole tools require two dedicated control lines to apply a pressure differential across a piston seal in order to translate an actuating device such as a mandrel or other similar component. This actuating device may be coupled or attached to a valve, such as a barrier or sliding sleeve valve, among others, in addition to other downhole tools or devices. For example, the valve may separate two zones of a formation or control the flow of fluid from the formation into the production tubing. However, the use of two individual control lines may add to the overall complexity of a downhole completion and occupy an increasingly limited space in a downhole environment. In addition, two control lines may raise the risk that one or both of the control lines is damaged during run in and/or operation. If there is a threshold level of pressure existing in the control lines, a leak in one control line may cause an inadvertent actuation of a downhole device as the threshold pressure from the other line is applied across the piston. Such a situation may significantly increase the risk of a catastrophic event, such as the unintentional discharge of hydrocarbons into the environment resulting from the inadvertent opening a safety valve for example. A single control line may provide increased levels of efficiency and reliability along with decreased amounts of complexity and space utilization.